I was recently reading about the origin of sex as one of the biggest mysteries left in evolutionary biology. All of the explanations I have read seem to focus on some long-term or group selection type advantage. ‘For the good of the species’ and that sort of thing. I’m always a little wary of these sorts of explanations and I really don’t understand why an explanation at the level of the individual or the gene fails. I’ve been thinking about it quite a lot and I came up with what seemed to me a reasonable scenario. Perhaps someone could read a very quick summary and tell me if there’s anything wrong with the idea.
The process would begin with the emergence of a sort of ‘proto-male’ in an exclusively ‘female’, asexually reproducing population. This individual learns the trick of copying and pasting some of its genes into another individual, perhaps with something like a virus as an intermediary. It might not initially be 50% of its genes which are transferred, it could be much less and the individual might still gain an advantage in that it can reproduce with multiple partners without having to expend the resources necessary for cell division.
This might seem to the detriment of the ‘impregnated’ individual. After all, they have just suffered a substantial reduction in the number of genes they pass on to each offspring and they still have to expend the energy of actually producing those offspring. However, each of those offspring would also have some chance of inheriting the ‘freeloading’ phenotype.
There would be some advantage to being impregnated in this manner at least some of the time, as your own genes could hitch a ride with the body-hopping genes of your impregnator. By allowing your own reproductive mechanism to be hijacked and reprogrammed to produce another individual’s genes, you also allow the possibility of every other individual in the population having their own machinery redirected to the production of offspring for you.
The benefits of sex seem obvious if you are a male and by extension, equally to a female with a probability of producing male offspring.
There would be competition as to which of the parents contributed the most genes and this would presumably stabilise at about 50% each.
Am I just being really naïve here? I’m untrained in biology, as I’m sure you can tell, so I wouldn’t be at all surprised if what I just said was complete nonsense. If so, thanks for reading it anyway.